Ilya Usoskin, Mr. - Prof.
Sodankylä Geophysical Observatory, University of Oulu, Finland
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Session 4 - Poster

The Maunder minimum: A reassessment from multiple datasets

I. Usoskin, Sodankylä Geophysical Observatory, University of Oulu, Finland
       

It is a current paradigm that the Maunder minimum (MM) in 1645-1715 was a period of greatly suppressed, but not completely vanished, solar activity. However, because of uncertainties related mostly to ambiguity of some historical sunspot observation records, the exact level of solar activity during the MM is somewhat unclear, leaving room for continuous discussions and speculations. Here we provide a full reassessment of the Maunder minimum using all the available datasets: augmented sunspot counts and drawings; revisited historical archives; both well-known and newly revealed records of auroral observations; cosmic ray variability via cosmogenic isotope. We show that, while the exact level of the activity is not easy to determine, the Sun indeed exhibited exceptionally low magnetic activity during the MM with very low solar surface magnetic activity, low intensity of the interplanetary magnetic field, as well as lower frequency and higher geographical latitude of auroral occurrence.